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Interpretive Handbook

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Test 83917 :
Eastern Equine Encephalitis Antibody Panel, IgG and IgM, Spinal Fluid

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Eastern equine encephalitis (EEE) is within the alphavirus group. It is a low-prevalence cause of human disease in the Eastern and Gulf Coast states. EEE is maintained by a cycle of mosquito/wild bird transmission, peaking in the summer and early fall, when man may become an adventitious host. The most common clinically apparent manifestation is a mild undifferentiated febrile illness, usually with headache.

 

Central nervous system involvement is demonstrated in only a minority of infected individuals, and is more abrupt and more severe than with other arboviruses, with children being more susceptible to severe disease. Fatality rates are approximately 70%.

 

Infections with arboviruses can occur at any age. The age distribution depends on the degree of exposure to the particular transmitting arthropod, relating to age, sex, and occupational, vocational, and recreational habits of the individuals. Once humans have been infected, the severity of the host response may be influenced by age.

Useful For Suggests clinical disorders or settings where the test may be helpful

Aiding the diagnosis of Eastern equine encephalitis

Interpretation Provides information to assist in interpretation of the test results

Detection of organism-specific antibodies in the cerebrospinal fluid (CSF) may suggest central nervous system infection. However, these results are unable to distinguish between intrathecal antibodies and serum antibodies introduced into the CSF at the time of lumbar puncture or from a breakdown in the blood-brain barrier. The results should be interpreted with other laboratory and clinical data prior to a diagnosis of central nervous system infection.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

All results must be correlated with clinical history and other data available to the attending physician.

 

False-positive results may be caused by breakdown of the blood-brain barrier, or by the introduction of blood into the cerebrospinal fluid at collection.

 

Eastern equine encephalitis viruses show some cross-reactivity; however, antibody response to the infection virus is typically at least 8-fold higher.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

IgG: <1:10

IgM: <1:10

Reference values apply to all ages.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Gonzalez-Scarano F, Nathanson N: Bunyaviruses. In Fields Virology. Volume 1. Second edition. Edited by BM Fields, DM Knipe. New York, Raven Press, 1990, pp 1195-1228

2. Donat JF, Rhodes KH, Groover RV, Smith TF: Etiology and outcome in 42 children with acute nonbacterial meningoencephalitis. Mayo Clin Proc 1980:55:156-160

3. Tsai TF: Arboviruses. In Manual of Clinical Microbiology. Seventh edition. Edited by PR Murray, EF Baron, MA Pfaller, et al. Washington, DC, American Society for Microbiology, 1999, pp 1107-1124

4. Calisher CH: Medically important arboviruses of the United States and Canada. Clin Microbiol Rev 1994;7:89-116


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